| SYNTHESIS |
Fumaric acid prepolymer was prepared by adding 40 g (0.34 mole) of fumaric acid to 500 ml refluxing acetic anhydride. The reaction was continued for five hours. The clear yellow-brown solution was left to crystallize at -20.degree. C. for three days. The white crystalline precipitate was then filtered and washed with dry ether to yield 25 g (45% yield). The melting point of the prepolymer was 75.degree. C, IR (KBr, pelat, cm.sup.-1).nu..sub.C.dbd.C 3070 (sharp), .nu..sub.anhydride 1800, 1735. 'H-NMR (CDC13, ppm) 6.92 (s,2H), 2.32 (s,6H). The prepolymers underwent melt polycondensation as follows. In a typical reaction, 4.0 g (0.034 mole) fumaric acid prepolymer was placed in a glass tube with a side arm and polymerized at 180.degree. C. under vacuum of less than 100 microns with an acetone/dry ice trap to collect the acetic anhydride formed in the polymerization. After ten minutes the melt turned to a creamy solid. Polymerization was stopped at 30 minutes. The creamy solid was ground to powder and washed with dry ether to yield 1.8 grams (95%). The polymer melting point was 248-249.degree. C. with some decomposition. Elemental analysis: C --48.45, H--2.11 (calculated C --48.98, H--2.0).
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